Wet powder film-forming compositions

ABSTRACT

An improved wet powder, edible, film-forming composition for use in coating tablets and capsules consists essentially of powdered pigment particles, a film-forming, water soluble or water-dispersible, edible polymer and up to approximately 30% by weight of water. Such compositions are formed by blending the pigment particles and the polymer and applying the water onto the pigment-polymer blend in atomized form. Similar wet powder, edible, clear, film-forming compositions for use in coating tablets and capsules with a clear coating consist essentially of a film-forming, water soluble or water-dispersible, clear, edible polymer and up to approximately 30% by weight of water and are formed by applying the water onto the polymer in atomized form. The application of water in this manner preconditions the polymer and permits the preparation of smooth stable coating suspensions upon dilution with additional water and without the formation of fish eyes.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of Ser. No. 07/801,201, filed Dec. 9,1991, now abandoned which is continuation-in-part of application Ser.No. 630,815, filed Dec. 20, 1990, abandoned.

BACKGROUND OF THE INVENTION

This invention relates to film-forming or film coating compositions foruse in the film coating of pharmaceutical tablets and the like and, moreparticularly, to such compositions in the form of wet powder blends orwet powder, clear, film-forming compositions.

Signorino U.S. Pat. No. 3,981,984 discloses edible concentrated pigmentsuspension in which pigments are suspended in non-aqueous solvents. Suchpigment suspensions are shipped, for example, to pharmaceuticalmanufacturers who mix them with polymer solutions to form coatingsuspensions used for coating tablets and the like. Each of the pigmentsuspensions, polymer solutions and coating suspensions formed therefromare in a non-aqueous solvent.

Porter et al. U.S. Pat. No. 4,543,370 discloses a dry edible filmcoating composition for use in pharmaceuticals, confectionary and foodwhich comprises a mixture including pigment particles, polymerparticles, a polymer plasticizer such as polyethylene glycol 400 and,advantageously, a surfactant such as dioctyl sodium sulfosuccinate.According to the patentees, such a film coating composition responds toa long standing desire to provide a dry edible film coating compositionwhich can be constituted with solvent by the customer, that eliminatesthe problem of shipping of pigment dispersions containing aqueous ornon-aqueous solvents, and also makes shipping less expensive byeliminating the weight of the solvents. In U.S. Pat. No. 4,543,370 it isstated to be known in the prior art to mix a dry polymer powder withpigment particles and to grind the mixture to obtain a drypolymer-pigment mixture which is then ground into a fine powder mixture.However, as further stated in this patent, when this finepolymer-pigment mixture is stirred into water and dispersed, the polymermakes lumps and fish eyes because it agglomerates and the resultantdispersion is not uniform. When this polymer-pigment dispersion is usedas a coating dispersion and is coated onto tablets and the like, unlessthe dispersion is left to solvate for a considerable period of time likeovernight, the coating is lumpy and not uniform.

The dry coating compositions of U.S. Pat. No. 4,543,370 are stated to beuseful within an hour of being made up and not to require an overnightwaiting period as was required by prior art aqueous and non-aqueoussystems.

Heinze U.S. Pat. No. 4,636,261 discloses dry mixtures of powdered ediblepigment particles and a dispersing agent which prevents agglomerationand facilitates dispersion into solution. The dispersing agent may bethe salt of an organic compound containing one to four carboxylic acidgroups or a salt of phosphoric acid.

In the preparation of clear film coating compositions for coatingaspirin tablets and the like, it has heretofore been the practice todissolve or disperse a polymer such as hydroxypropylmethyl cellulose inwater and then wait for a period of 18 hours or so before applying theresulting polymer solution or dispersion to tablets or the like. Such awaiting period has been deemed necessary in order to rid the solution ordispersion of fish eyes and allow water to penetrate into or hydrate thepolymer gel particles (fish eyes) which form upon dissolving ordispersing the polymer in water. While pre-conditioned orsurface-treated polymers are available, it is necessary to add a basematerial to such polymers in order to allow the polymers to becomehydrated and dissolve or disperse in water.

There remains a need for further improvements in film coatingcompositions with regard to their ability to disperse color in thecoating of tablets, capsules and the like and their usefulness for thispurpose upon preparation or within a short time thereafter.

SUMMARY OF THE INVENTION

Among the objects of the present invention may be noted the provision offilm-forming compositions useful in coating tablets, capsules and thelike which are produced in the form of wet powder blends; the provisionof clear film-forming compositions for use in coating tablets andcapsules with a clear coating; the provision of such compositions whichare capable of forming stable suspensions for coating tablets, capsulesor the like upon dilution with additional water; the provision ofcompositions of this type which can be used for coating tablets andcapsules shortly after being combined with additional water and aplasticizer; and the provision of methods of making such film-formingcompositions. Other objects and features will be in part apparent and inpart pointed out hereinafter.

Briefly, the present invention is directed to a wet powder, edible,film-forming composition for use in coating tablets, capsules and thelike which consists essentially of powdered pigment particles, afilm-forming, water-soluble or water-dispersible, edible polymer andbetween approximately 1% and approximately 30% by weight of water, thecomposition being formed by blending the pigment particles and polymerand applying the water onto the pigment-polymer blend in atomized formand the composition being capable of forming a stable suspension upondilution with additional water. Preferably, the composition alsocontains a dispersing agent such as an alkali metal or ammonium salt ofethylene diamine tetraacetic acid which lowers the surface tension ofwater in the composition.

The invention is also directed to a method of making a wet powder,edible, film-forming composition of the type described above for use incoating tablets, capsules and the like which comprises (a) blendingpowdered pigment particles and a film-forming, water-soluble orwater-dispersible edible polymer; and (b) applying water or an aqueoussolution of the above-mentioned dispersing agent onto thepigment-polymer blend in atomized form, the composition containingbetween approximately 1% and approximately 30% by weight of water.

The invention, in another embodiment, is further directed to a wetpowder, edible, clear, film-forming composition for use in coatingtablets, capsules and the like with a clear coating consistingessentially of a clear, film-forming, water-soluble orwater-dispersible, edible polymer and between approximately 1% andapproximately 30% by weight of water, the compositions being formed byapplying water onto the polymer in atomized form and the compositionbeing capable of forming a stable suspension upon dilution withadditional water without the formation of fish eyes. The composition ofthis emobidment of the invention preferably also contains a dispersingagent of the aforementioned type, and the invention further encompassesa method of making a clear, film-forming composition of this embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with the present invention, it has now been unexpectedlyfound that useful wet powder, edible, film-forming compositions forcoating tablets, capsules and the like may be formulated by blendingpowdered pigment particles with a film-forming, water-soluble orwater-dispersible, edible polymer and applying water onto thepigment-polymer blend in atomized form. When formulated in this manner,the resulting film-forming compositions have been found capable oftolerating up to approximately 30% by weight water while yet remainingcapable of forming a stable suspension upon dilution with additionalwater. Also, the film-forming compositions prepared in accordance withthe present invention and containing between approximately 1% andapproximately 30% by weight of water do not lump up or contain fish eyesand, when combined with additional water and a plasticizer provide asmooth, uniform coating for pharmaceutical tablets, capsules and thelike. Optionally, but preferably, the film-forming compositions of theinvention also contain a dispersing agent constituted by an acid saltwhich lowers the surface tension of the water in the composition andwhich in turn lowers the viscosity of the final coating suspension tothereby provide improved and smoother coatings for tablets and the like.

It is believed that the addition or application of water onto thepigment-polymer blend in atomized form in accordance with the inventionadvantageously preconditions the polymer and avoids clumping or theformation of fish eyes when the compositions of the invention are addedto water to form coating suspensions. Thus, by applying the water inatomized form, the water becomes uniformly distributed over or to allpolymer particles, the pigment particles adhere to the polymer particlesand the polymer is preconditioned so that hydration of the polymer isexpedited when the pigment-polymer blend is dispersed in water to form acoating suspension. Accordingly, the present invention achieves theadvantageous preconditioning of the blend of pigment and polymer causingthe blend to readily disperse and dissolve in water in forming thedesired coating suspension without deleterious lumping or agglomeration.Moreover, through the present invention, it becomes possible to preparesmooth coating suspensions which can be used immediately or within 30minutes for the coating of tablets or the like.

In the practice of the present invention, powdered pigment particles arefirst blended or admixed with a film-forming, water-soluble orwater-dispersible, edible polymer. Water or an aqueous solution of adispersing agent which lowers the surface tension of water is thenapplied onto the pigment-polymer blend in atomized form to produce afilm-forming composition containing between approximately 1% andapproximately 30% by weight of water. For use as the powdered pigmentcomponent of the compositions of the invention, any FDA approved ediblenatural or synthetic colorant may be employed. Useful pigments include,but are not limited to, FD&C and D&C dyes, FD&C and D&C lakes, titaniumdioxide, iron oxides, talc, alumina, silica and natural colorants.Typically, the powdered pigment particles may be constituted by acombination of a lake and titanium dioxide or iron oxide. The particlesize of the powdered pigment particles is not critical, but the finerthe particle size, the better the results achieved through the presentinvention. The particle size of commercially available pigments known tothose in the art renders them satisfactory for use in the compositionsof the invention.

In order to be useful in the invention, the film-forming, edible polymercomponent must be water-soluble or water-dispersible. Useful polymers ofthis type include methyl cellulose, hydroxypropylmethyl cellulose,hydroxypropyl cellulose, polyvinyl pyrrolidone, maltodextrin,polydextrose, modified starches (such as "Purity Gum 59" marketed byNational Starch) and natural gums such as gum tragacanth, gum acacia andxanthan gums, with hydroxypropylmethyl cellulose being the preferredpolymer. Mixtures of such polymers may also be used. It is preferredthat the polymer be in powdered form, but the particular particle sizeof the polymer is not critical in the practice of the invention.

After the powdered pigment and polymer have been blended until uniform,the desired amount of water per se or in the form of an aqueous solutionof a dispersing agent is added with intense mixing so that the water oraqueous solution of the dispersing agent is applied to thepigment-polymer blend in atomized form. This can be accomplished, forexample, by blending the powdered pigment and polymer in a PK Blender ora Littleford FM 130 Blender and adding the water or aqueous solution ofdispersing agent with intense mixing by fine atomization into theblender chamber where the powdered pigment and polymer are being mixed.Preferably, the water or aqueous solution is added slowly and theresulting water-containing blend or composition is mixed intensely afteraddition of the water.

It has been found that film-forming compositions prepared in this mannermay contain up to approximately 30% by weight of water and yet remaincapable of forming a stable suspension useful for coating tablets andthe like upon dilution with additional water. It should be noted thatwhere FD&C lakes are employed as pigments, they may contain up to 15% byweight of water and that the polymer component may likewise contain upto 4% to 6% by weight of water. The water added through the practice ofthis invention is additional water over and above that contained in thepigment and polymer components and, as stated, may range fromapproximately 1% to 30% by weight, with approximately 2% to 10% byweight being the preferred among and approximately 5% to 9% by weightbeing the most preferred amount.

In an optional but highly preferred embodiment, a dispersing agent whichlowers the surface tension of water is incorporated into thefilm-forming compositions of the invention. The dispersing agent isconstituted by an acid salt which functions to lower the surface tensionof water in the compositions and illustrative acid salts which performthis function include the alkali metal and ammonium salts of ethylenediamine tetraacetic acid, nitrilo triaacetic acid, citric acid,phosphoric acid, tartaric acid, glycolic acid, malic acid, lactic acid,acetic acid and benzoic acid. It will be understood that other acidsalts which function to lower the surface tension of water in thecompositions may also be employed in the practice of the invention.Sodium salts of ethylene diamine tetraacetic acid represent thepreferred dispersing agents for use in the practice of the invention.The dispersing agent is generally incorporated into the film-formingcompositions in the form of aqueous solutions of such acid salts, suchaqueous solutions being applied to the pigment-polymer blends aspreviously described and providing the amount of water to be added tothe compositions as well as acting as the vehicle for the application ofthe dispersing agent to the pigment-polymer blends. Alternatively, butless preferably, the dispersing agent may be added in powder form to thepigment-polymer blend with the water being applied to the resultingblend of the three components in atomized form. The dispersing agent notonly lowers the surface tension of the water in the film-formingcompositions of the invention but also lowers the viscosity of thecoating suspensions prepared from such compositions thereby providingsmaller suspension droplets and smoother coatings for tablets and thelike. While the invention may be practiced without the addition of adispersing agent to the film-forming compositions, it has been foundthat the-incorporation of a dispersing agent produces a better colordevelopment and quality of coating for tablets and the like.

The film-forming compositions of the invention are shelf-stable forextended periods of time without the use of preservatives and are notprone to settling or other break-downs. Further, it is believed thatsuch compositions remain free from bacteria formation such as may benormally caused by the solvent in liquid pigment dispersions.

To prepare coating suspensions for use in coating tablets and the like,the film-forming compositions of the invention are added to water and aplasticizer in accordance with conventional practice. The coatingsuspensions so prepared may be applied immediately to tablets without awaiting period such as overnight as is required with certain prior artsystems. Any of the plasticizers known to the art such as polyethyleneglycol 400, glycerin, propylene glycol, glycerine triacetate, triethylcitrate, tributyl citrate or diethyl phthalate may be used informulating coating suspensions from the wet film-forming compositionsof the invention.

In another, but less preferred, embodiment of the invention, aplasticizer may be incorporated into the wet film-forming compositionsof the invention so that the resulting compositions may be simply addedto water in order to form useful coating suspensions for coating tabletsand the like.

In preparing the wet powder, edible, film-forming compositions of theinvention, the proportions of pigment and polymer employed are notcritical. In general, where the ratio of pigment to polymer is high, aflat appearing film of lower quality will be obtained whereas with lowerratios of pigment to polymer, a more glossy film finish and better filmproperties will be obtained. For acceptable results, the weight ratio ofpolymer to pigment should range between 1.5:1 and 3:1 with the ratio ofapproximately 2.5:1 being preferred where the pigment component isprimarily constituted by a lake.

The proportion of dispersing agent incorporated into the film-formingcompositions of the invention may vary widely but, in general, mayconstitute between 0.1 to 5.0% by weight based on the weight of thepigment and polymer components and more preferably between 0.5 to 2.0%by weight.

In another embodiment and in further accordance with the invention, ithas also been unexpectedly found that useful wet powder, edible, clearfilm-forming compositions for coating tablets, capsules and the likewith a clear coating may be formulated by applying water onto afilm-forming, water-soluble or water-dispersible, edible, clear polymerin atomized form. Here again, when formulated in this manner, theresulting clear, film-forming compositions have been found capable oftolerating up to approximately 30% by weight water without forming fisheyes while yet remaining capable of forming a stable suspension upondilution with additional water. Such clear, film-forming compositionsprepared as described above and containing between approximately 1% and30% by weight of water do not lump up or contain fish eyes and thereforerequire no long waiting period or pretreatment of the polymer componentbefore being used to make coating compositions. When combined withadditional water and a plasticizer, such clear, film-formingcompositions yield a smooth, uniform coating composition for coatingpharmaceutical tablets, capsules and the like with a clear coating. Whena plasticizer is incorporated, water is first applied onto the polymerin atomized form following which the plasticizer is sprayed onto theresulting composition. Through this embodiment of the invention, itbecomes possible to prepare smooth, clear, coating suspensions which canbe used immediately or within 30 minutes for providing tablets, capsulesor the like with a clear coating. In this embodiment of the invention,it is also optional, but preferable, for the clear, film-formingcompositions to contain a dispersing agent constituted by an acid saltwhich lowers the surface tension of the water in the composition. Any ofthe dispersing agents enumerated above may be used in this embodiment ofthe invention.

In forming clear, film-forming compositions as above described, it isbelieved that the application of water onto the polymer advantageouslypreconditions the polymer as in the case of the pigment-polymer blenddescribed above and avoids clumping or the formation of fish eyes eitherupon application of the water or when the resulting clear, film-formingcompositions of the invention are added to water to form coatingsuspensions. Upon the application of water to a clear polymer aspreviously described, granules or an agglomeration of polymer particlesare formed which unexpectedly go into solution readily in contrast tothe addition of a polymer per se to water which tends to clump or formfish eyes. In forming clear, film-forming compositions of the inventionin accordance with this additional embodiment, the same film-forming,water-soluble or water-dispersible, edible polymers, dispersing agentsand plasticizers disclosed above may be employed, but the resultingcompositions are clear because they contain no pigment component. Also,such clear, film-forming compositions can be prepared using a PK Blenderor a Littleford FM 130 Blender which insure that the water is applied tothe polymer in atomized form. The water may also be applied in atomizedform by means of an aqueous solution of the dispersing agent where thelatter is optionally but preferably incorporated into the film-formingcompositions.

The following examples illustrate the practice of the invention.

EXAMPLE 1

The following ingredients were charged to a Littleford FM 130 blender:

    ______________________________________    Hydroxypropylmethyl cellulose                             43 lb.    Titanium dioxide         26 lb.    FD&C Yellow 6 Low dye lake                             1 lb.    ______________________________________

The ingredients were blended for two minutes to form a pigment-polymerblend. 3.5 lb. of a 10% aqueous sodium citrate solution was sprayed ontothe pigment-polymer blend with mixing in approximately 2.5 minutes andthen mixed for 1 minute after addition of the sodium citrate solutionwas complete. This effected application of the sodium citrate solutiononto the pigment-polymer blend in atomized form. A dustless,free-flowing powdered film-forming composition was produced.

EXAMPLE 2

The following ingredients were charged to a Littleford W-10 mixer:

    ______________________________________    Hydroxypropylmethyl cellulose                             1.36 kg.    Titanium dioxide         0.35 kg.    FD&C Yellow 5 High dye lake                             0.20 kg.    FD&C Yellow 6 High dye lake                             0.03 kg.    ______________________________________

The ingredients were mixed for three minutes to form a pigment-polymerblend. 60 grams of a 10% aqueous solution of the tetrasodium salt ofethylene diamine tetraacetic acid was then sprayed onto thepigment-polymer blend in one minute, with mixing continued for oneminute after the addition of the 10% solution was complete. A dustless,free-flowing powder was produced.

EXAMPLE 3

The following ingredients were charged to a PK Blender Model LBC-2P:

    ______________________________________    Hydroxypropylmethyl cellulose                             400 g.    Titanium dioxide         100 g.    FD&C Yellow 6 High dye lake                             100 g.    ______________________________________

The ingredients were mixed for four minutes to form a pigment-polymerblend. 60 grams of water was then sprayed onto the pigment-polymer blendin two minutes, with mixing continued for one minute after the additionof the water was complete. A dustless, free-flowing powder was produced.

EXAMPLE 4

Example 3 was repeated using 60 grams of a 10% aqueous solution of thetetrasodium salt of ethylene diamine tetraacetic acid in place of water.A dustless, free-flowing powder was produced.

EXAMPLE 5

Example 3 was repeated using 60 grams of a 10% aqueous solution ofsodium citrate in place of water. A dustless, free-flowing powder wasproduced.

EXAMPLE 6

Example 3 was repeated using 30 grams of a 10% aqueous solution ofsodium dibasic phosphate (Na₂ HPO₄) in place of water. A dustless,free-flowing powder was produced.

EXAMPLE 7

Example 3 was repeated using FD&C Red 40 in place of FD&C Yellow 6 Highdye lake. A dustless, free-flowing powder was produced.

EXAMPLE 8

Example 3 was repeated using FD&C Red 40 in place of FD&C Yellow 6 Highdye lake and 30 grams of a 10% aqueous solution of the trisodium salt ofethylene diamine tetraacetic acid in place of water. A dustless,free-flowing powder was produced.

EXAMPLE 9

A coating suspension was prepared as follows: 87.5 grams of water and1.5 grams of polyethylene glycol 400 were charged to a beaker. Whilestirring the beaker contents vigorously, 11 grams of the powder producedin Example 4 was added to the beaker. The powder readily dispersed andthe suspension which formed thickened and became very smooth in 15minutes.

The resulting coating suspension was applied immediately to tablets in a4" Wurster Column, and a smooth glossy coating on the tablets wasachieved in 15 minutes.

EXAMPLE 10

The following ingredients were charged to a PK Blender Model LBC-2P:

    ______________________________________    Hydroxypropylmethyl cellulose                             360 g.    Maltrin M-100 (Maltodextrin)                             240 g.    ______________________________________

The above polymer ingredients should preferably be distributed equallyin each shell of the blender and should be 1/2 to 3/4 the way up theintensifier bar of the blender. The blender was closed and mixing of thedry blend was carried out for 4 to 5 minutes with both the shell andintensifier bar mixing being used. After the polymer ingredients werethus blended, mixing with both the shell and intensifier bar wascontinued and the liquid feed pump was turned on. 38 grams of a 10%aqueous solution of sodium citrate was fed onto the polymer blend inatomized form followed by the addition of 48 grams of polyethyleneglycol 400 as a plasticizer. After the addition of the sodium citratesolution and plasticizer, the liquid feed pump was allowed to run for 1minute to clear the lines. After the liquid feed pump was shut off, theshell and intensifier bar were allowed to mix for 30 seconds and theblender was shut off. A dustless, free-flowing powder was produced.

EXAMPLE 11

The composition of Example 10 was used to make a coating solution. 863.2grams of water were added to a container equipped with a variable speedmixer. The mixer was started and once a vortex was formed, 136.8 gramsof the composition of Example 10 was added in a steady and consistentmanner. The speed of the mixer was increased as the solution became moreviscous, with the composition being added to the center of the vortexfor best mixing. After the complete addition of the Example 10composition, the speed of the mixer was reduced to reduce aeration ofthe solution. The sides of the container were scraped to remove anyclumps which were added to the center of the solution. Mixing wascontinued for 30 minutes to produce a smooth, clear coating solution.

EXAMPLE 12

The clear, coating solution of Example 11 was used to coat tablets bycolumn or pan coating. The coating solution of Example 11 was charged tothe liquid feed system and the tablets to be coated were charged to thecoating equipment. The tablets were warmed and the coating solution wassprayed onto the tablets. The resulting tablets had a smooth, clear,glossy coating.

EXAMPLE 13

The procedure of Example 10 was generally followed to produce a wetpowder, edible, clear, film-forming composition having the followingcomposition:

    ______________________________________    Component            Wt. %    ______________________________________    Hydroxypropylmethyl cellulose                         68.2    Hydroxypropyl cellulose                         22.8    Water                9.0    ______________________________________

A dustless, free-flowing powder was produced.

EXAMPLE 14

The procedure of Example 10 was generally followed to produce a wetpowder, edible, clear, film-forming composition having the followingcomposition:

    ______________________________________    Component            Wt. %    ______________________________________    Hydroxypropylmethyl cellulose                         94.6    Sodium citrate       0.4    Water                5.0    ______________________________________

A dustless, free-flowing powder was produced.

EXAMPLE 15

The procedure of Example 10 was generally followed to produce a wetpowder, edible, clear, film-forming composition having the followingcomposition:

    ______________________________________    Component            Wt. %    ______________________________________    Hydroxypropylmethyl cellulose                         91.5    Sodium citrate       0.4    Water                8.1    ______________________________________

A dustless, free-flowing powder was produced.

EXAMPLE 16

The procedure of Example 10 was generally followed to produce a wetpowder, edible, clear, film-forming composition having the followingcomposition:

    ______________________________________    Component          Wt. %    ______________________________________    Hydroxypropylmethyl                       84.0    cellulose    Sodium citrate     1.0    Talc               5.0    Glycerin triacetate                       5.0    Water              5.0    ______________________________________

A dustless, free-flowing powder was produced.

EXAMPLE 17

The procedure of Example 10 was generally followed to produce a wetpowder, edible, clear, film-forming composition having the followingcomposition:

    ______________________________________    Component            Wt. %    ______________________________________    Hydroxypropylmethyl cellulose                         87.70    Sodium citrate       0.14    Talc                 3.90    Glycerin triacetate  4.30    Water                3.90    ______________________________________

A dustless, free-flowing powder was produced.

EXAMPLE 18

The procedure of Example 10 was generally followed to produce a wetpowder, edible, clear, film-forming composition having the followingcomposition:

    ______________________________________    Component            Wt. %    ______________________________________    Hydroxypropylmethyl cellulose                         90.3    Tetrasodium ethylene diamine                         0.5    tetraacetate    Polyethylene glycol  4.5    Water                4.7    ______________________________________

A dustless, free-flowing powder was produced.

EXAMPLE 19

The procedure of Example 10 was generally followed to produce a wetpowder, edible, clear, film-forming composition having the followingcomposition:

    ______________________________________    Component            Wt. %    ______________________________________    Hydroxypropylmethyl cellulose                         85.4    Tetrasodium ethylene diamine                         0.5    tetraacetate    Polyethylene glycol  4.3    Water                4.6    ______________________________________

A dustless, free-flowing powder was produced.

EXAMPLE 20

The procedure of Example 10 was generally followed to produce a wetpowder, edible, clear, film-forming composition having the followingcomposition:

    ______________________________________    Component            Wt. %    ______________________________________    Hydroxypropylmethyl cellulose                         91.5    Triethyl citrate     4.6    Water                3.8    ______________________________________

A dustless, free-flowing powder was produced.

EXAMPLE 21

The procedure of Example 10 was generally followed to produce a wetpowder, edible, clear, film-forming composition having the followingcomposition:

    ______________________________________    Component            Wt. %    ______________________________________    Hydroxypropylmethyl cellulose                         84.50    Sodium citrate       0.35    Glycerine triacetate 8.50    Talc                 3.50    Water                3.20    ______________________________________

A dustless, free-flowing powder was produced.

EXAMPLE 22

The procedure of Example 10 was generally followed to produce a wetpowder, edible, clear, film-forming composition having the followingcomposition:

    ______________________________________    Component            Wt. %    ______________________________________    Hydroxypropylmethyl cellulose                         84.50    Sodium citrate       0.35    Glycerin triacetate  8.00    Talc                 4.00    Water                3.20    ______________________________________

A dustless, free-flowing powder was produced.

EXAMPLE 23

The procedure of Example 10 was generally followed to produce a wetpowder, edible, clear, film-forming composition having the followingcomposition:

    ______________________________________    Component            Wt. %    ______________________________________    Hydroxypropylmethyl cellulose                         85.50    Sodium citrate       0.35    Glycerin triacetate  6.00    Talc                 5.00    Water                3.20    ______________________________________

A dustless, free-flowing powder was produced.

EXAMPLE 24

The procedure of Example 10 was generally followed to produce a wetpowder, edible, clear, film-forming composition having the followingcomposition:

    ______________________________________    Component            Wt. %    ______________________________________    Hydroxypropylmethyl cellulose                         78.70    Sodium citrate       0.55    Polyvinyl pyrrolidone                         15.70    Water                5.00    ______________________________________

A dustless, free-flowing powder was produced.

EXAMPLE 25

The procedure of Example 10 was generally followed to produce a wetpowder, edible, clear, film-forming composition having the followingcomposition:

    ______________________________________    Component            Wt. %    ______________________________________    Hydroxypropylmethyl cellulose                         90.20    Tetrasodium ethylene diamine                         0.53    tetraacetate    Polyethylene glycol  4.50    Water                4.70    ______________________________________

A dustless, free-flowing powder was produced.

EXAMPLE 26

The procedure of Example 10 was generally followed to produce a wetpowder, edible, clear, film-forming composition having the followingcomposition:

    ______________________________________    Component            Wt. %    ______________________________________    Hydroxypropylmethyl cellulose                         95.0    Water                5.0    ______________________________________

A dustless, free-flowing powder was produced.

EXAMPLE 27

The procedure of Example 10 was generally followed to produce a wetpowder, edible, clear, film-forming composition having the followingcomposition:

    ______________________________________    Component            Wt. %    ______________________________________    Hydroxypropylmethyl cellulose                         90.0    Sodium citrate       0.4    Polyethylene glycol  6.0    Water                3.6    ______________________________________

A dustless, free-flowing powder was produced.

EXAMPLE 28

The procedure of Example 10 was generally followed to produce a wetpowder, edible, clear, film-forming composition having the followingcomposition:

    ______________________________________    Component            Wt. %    ______________________________________    Hydroxypropylmethyl cellulose                         45.75    Modified starch ("Purity                         45.75    Gum 59", National Starch)    Sodium citrate       0.50    Water                8.00    ______________________________________

A dustless, free-flowing powder was produced.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above methods and productswithout departing from the scope of the invention, it is intended thatall matter contained in the above description shall be interpreted asillustrative and not in a limiting sense.

What is claimed is:
 1. A wet powder, edible, film-forming compositionfor use in coating tablets and capsules comprising powdered pigmentparticles, a film-forming, water soluble or water-dispersible, ediblepolymer and between approximately 1% and approximately 30% by weight ofwater, said composition being formed by blending said pigment particlesand said polymer and applying said water onto the pigment-polymer blendin atomized form and said composition being capable of forming a stablesuspension upon dilution with additional water.
 2. The wet powder,edible, film-forming composition as set forth in claim 1 wherein saidpolymer is selected from the group consisting of methyl cellulose,hydroxypropylmethyl cellulose, hydroxypropyl cellulose, polyvinylpyrrolidone, maltodextrin, polydextrose, modified starches and a naturalgum selected from the group consisting of gum tragacanth, gum acacia anda xanthan gum.
 3. The wet powder, edible, film-forming composition asset forth in claim 1 wherein said polymer is hydroxypropylmethylcellulose.
 4. The wet powder, edible, film-forming composition as setforth in claim 1 wherein said composition contains from approximately 2%to 10% by weight of water.
 5. The wet powder, edible, film-formingcomposition as set forth in claim 1 wherein said composition containsfrom approximately 5% to 9% by weight of water.
 6. The wet powder,edible, film-forming composition as set forth in claim 1 wherein saidpigment particles are selected from the group consisting of FD&C and D&Cdyes, FD&C and D&C lakes, titanium dioxide, iron oxides, talc, alumina,silica and FD&C approved natural colorants.
 7. The wet powder, edible,film-forming composition as set forth in claim 1 wherein said pigmentparticles are constituted by a combination of a lake and titaniumdioxide or iron oxide.
 8. The wet powder, edible, film-formingcomposition as set forth in claim 1 wherein said compositionadditionally includes a plasticizer.
 9. A wet powder, edible,film-forming composition for use in coating tablets and capsulescomprising powdered pigment particles, a film-forming, water-soluble orwater-dispersible, edible polymer, between approximately 1% andapproximately 30% by weight of water, and a dispersing agent constitutedby an acid salt which lowers the surface tension of water in thecomposition, said composition being formed by blending said pigmentparticles and said polymer and applying an aqueous solution of saiddispersing agent onto the pigment-polymer blend and said compositionbeing capable of forming a stable suspension upon dilution withadditional water.
 10. The wet powder, edible, film-forming compositionas set forth in claim 9 wherein said acid salt is selected from thegroup consisting of the alkali metal and ammonium salts of ethylenediamine tetraacetic acid, nitrilo triacetic acid, citric acid,phosphoric acid, tartaric acid, glycolic acid, malic acid, lactic acid,acetic acid and benzoic acid.
 11. The wet powder, edible, film-formingcomposition as set forth in claim 9 wherein said acid salt is an alkalimetal or ammonium salt of ethylene diamine tetraacetic acid.
 12. The wetpowder, edible, film-forming composition as set forth in claim 9 whereinsaid polymer is selected from the group consisting of methyl cellulose,hydroxypropylmethyl cellulose, hydroxypropyl cellulose, polyvinylpyrrolidone, maltodextrin, polydextrose, modified starches and a naturalgum selected from the group consisting of gum tragacanth, gum acacia anda xanthan gum.
 13. The wet powder, edible, film-forming composition asset forth in claim 9 wherein said polymer is hydroxypropylmethylcellulose.
 14. The wet powder, edible, film-forming composition as setforth in claim 9 wherein said composition contains from approximately 2%to 10% by weight of water.
 15. The wet powder, edible, film-formingcomposition as set forth in claim 9 wherein said composition containsfrom approximately 5% to 9% by weight of water.
 16. The wet powder,edible, film-forming composition as set forth in claim 9 wherein saidpigment particles are selected from the group consisting of FD&C and D&Cdyes, FD&C and D&C lakes, titanium dioxide, iron oxides, talc, alumina,silica and FD&C approved natural colorants.
 17. The wet powder, edible,film-forming composition as set forth in claim 9 wherein said pigmentparticles are constituted by a combination of a lake and titaniumdioxide or iron oxide.
 18. The wet powder, edible, film-formingcomposition as set forth in claim 9 wherein said compositionadditionally includes a plasticizer.